Table 1. Rmsd Values for the Whole Protein, Fe–Fe Distances between the Two Hemes, Numbers of Interfacial Water Molecules, and Subunit Rotation Angles for the Averaged Refined Structures of the Intermediates (I₁, I₂, and I₃) and the Deoxy-HbI Crystal Structure (PDB Entry 4sdh(11)) with Respect to the HbI(CO)₂ Crystal Structure (PDB Entry 3sdh(11))^a.

	rmsd (Å)	Fe–Fe distance (Å)	number of interface water molecules	rotation angle (deg)
HbI(CO)2(3sdh)	–	18.4	11	–
deoxy-HbI (4sdh)	0.6	16.6	17	3.5
deoxy-HbI F97Y mutant (2aup)	0.6	17.2	6	3.4b
I1	0.4 (±0.05)	18.0 (±0.2)	9 (fixed)	–0.1 (±0.5)
I2	0.4 (±0.06)	17.9 (±0.3)	9 (fixed)	0.1 (±0.5)
I3(WT)	0.7 (±0.05)	16.6 (±0.2)	17 (fixed)	3.5 (±0.6)
I3(F97Y)	0.8 (±0.04)	18.0 (±0.2)	6 (fixed)	3.0 (±0.6)

^aValues in parentheses are standard deviations among the candidate structures.

^bThe subunit rotation angle for the deoxy-HbI F97Y mutant crystal structure (PDB entry 2aup)¹⁵ was calculated with respect to the HbI(CO)₂ F97Y mutant crystal structure (PDB entry 2auo).¹⁵